I think when these movies were first being made we had an expectation we could see stuff like Demon in a Bottle. In fact once Robert Downey Jr. got the role it intensified that expectation. Of course all that changed once the movie came out and kids started dressing up as Iron Man for Halloween and buying all the toys and merch. Suddenly you can't have an alcoholic superhero.

You can sort of do stuff like Tony getting tipsy or having a drinky drink or having fun with the ladies, but he can't hit rock bottom and become a full blown alcoholic.

In Iron Man 2 most of the time he was behaving and being responsible. He usually wasn't drinking and was instead drinking his health smoothies. So it wasn't like, he thought he messed up so badly he got depressed and drowning his depression with alcohol.